1. Field of the Invention
The present invention relates to a camera system having a camera body and a photographing lens which is detachably attached to the camera body, and having a communication system between the camera body and the photographing lens.
2. Description of the Related Art
Power zoom lenses (motorized zoom lenses) with an image size tracking mode, in which the camera can automatically zoom the lens to constantly capture the object at a pre-set image size regardless of the distance to the object, within the constraints of the focal length range, are known in the art. In recent camera systems having a camera body and an interchangeable photographing lens which is detachably attached to the camera body, if the above-described type of power zoom lens with the image size tracking mode is employed, the camera body prepares only data necessary for a CPU of the photographing lens to perform operations thereof in the image size tracking mode, and transmits such data to the photographing lens together with various control commands.
However, according to such a data transmission system of the camera system, if the development of an interchangeable photographing lens having one or more additional functions (e.g., a lens autofocus function) is intended, the camera body to which the photographing lens is mounted will need to prepare camera-status data necessary for the photographing lens to operate for each of all the functions of the photographing lens. This complicates various communication processes and controls of the camera system. On the other hand, if an interchangeable photographing lens having one or more new functions is mounted to a conventional type camera body, it is often the case that such new functions cannot be used and may cause the camera body to malfunction. Accordingly, the development of an interchangeable photographing lens having one or more new functions is difficult in conventional camera systems.
The present invention provides a camera system having a camera body and a photographing lens which is detachably attached to the camera body, and includes a communication system between the camera system and the photographing lens, wherein the camera system is designed so that the degree of freedom in further developing a photographing lens so as to have one or more additional new functions is increased, to thereby increase the general compatibility between pre-existing and newly developed photographing lenses for the camera body.
For example, in an embodiment, a camera system is provided, including a photographing lens including at least one of a lens memory, in which lens data on the photographing lens is stored, and a lens controller which controls operations of the photographing lens; and a camera body including a body controller which can communicate with at least one of the lens memory and the lens controller; a first power which can be supplied to the photographing lens; and a second power which can be supplied to the photographing lens. The photographing lens can be mounted to, and dismounted from, the camera body. The lens memory and the lens controller operate with the first power and the second power, respectively, when the photographing lens is mounted to the camera body. The body controller supplies the first power to the photographing lens to drive the lens memory to read out the lens data from the lens memory when the photographing lens is mounted to the camera body, and subsequently disables the lens memory and supplies the second power to the lens controller so that the body controller and the lens controller communicate with each other in the case where the body controller determines, from the lens data read out of the lens memory, that the photographing lens includes the lens controller.
The camera body can include a body communication line, a first body power line and a second body power line. The photographing lens can include a lens communication line, a first lens power line, and a second lens power line which are connected with the body communication line, the first body power line and the second body power line, respectively, when the photographing lens is mounted to the camera body. The camera body and the photographing lens can communicate with each other via the body communication line and the lens communication line. The camera body can supply the first power to the photographing lens via the first body power line and the first lens power line. Similarly, the camera body can supply the second power to the photographing lens via the second body power line and the second lens power line.
It is desirable for the body controller to include a control line for changing a state of the lens memory between an enabled state and a disabled state.
The camera body can transmit a first command, for making the lens controller enter a sleep mode, to the lens controller via the body communication line and the lens communication line, the lens controller entering the sleep mode upon receiving the first command; and the camera body can transmit a second command, for making the lens controller come out of the sleep mode, to the lens controller via the body communication line and the lens communication line, the lens controller coming out of the sleep mode upon receiving the second command.
It is beneficial for the power capacity of the second power to be substantially greater than the power capacity of the first power.
Alternatively, a camera body is provided to which a photographing lens can be mounted and dismounted, the photographing lens having at least one of a lens memory, in which lens data on the photographing lens is stored, and a lens controller which controls operations of the photographing lens, the camera body including a body controller which can communicate with at least one of the lens memory and the lens controller; a first power which can be supplied to the photographing lens; and a second power which can be supplied to the photographing lens. The lens memory and the lens controller operate with the first power and the second power, respectively, when the photographing lens is mounted to the camera body. The body controller supplies the first power to the photographing lens to drive the lens memory to read out the lens data from the lens memory when the photographing lens is mounted to the camera body, and subsequently disables the lens memory and supplies the second power to the lens controller so that the body controller and the lens controller communicate with each other in the case where the body controller determines, from the lens data read out of the lens memory, that the photographing lens includes the lens controller.
It is beneficial for the camera body to further include a body communication line, a first body power line and a second body power line, and the photographing lens to include a lens communication line, a first lens power line, and a second lens power line which are connected with the body communication line, the first body power line and the second body power line, respectively, when the photographing lens is mounted to the camera body. The camera body and the photographing lens communicate with each other via the body communication line and the lens communication line. The camera body supplies the first power to the photographing lens via the first body power line and the first lens power line. The camera body supplies the second power to the photographing lens via the second body power line and the second lens power line.
The body controller can include a control line for changing a state of the lens memory between an enabled state and a disabled state.
The camera body can transmit a first command, for making the lens controller enter a sleep mode, to the lens controller via the body communication line and the lens communication line, the lens controller entering the sleep mode upon receiving the first command; and the camera body can transmit a second command, for making the lens controller come out of the sleep mode, to the lens controller via the body communication line and the lens communication line, the lens controller coming out of the sleep mode upon receiving the second command.
A photographing lens which can be mounted to and dismounted from a camera body, can be provided, including a lens memory in which lens data on the photographing lens is stored, and a lens controller which controls operations of the photographing lens. The lens memory and the lens controller operate with a first power and a second power which are supplied from the camera body, respectively, when the photographing lens is mounted to the camera body. The lens memory is driven to output the lens data therefrom to the camera body under control of the camera body when the camera body supplies the first power to the lens memory. The lens memory is disabled, so that the lens controller communicates with the camera body, when the camera body supplies the second power to the lens controller.
The photographing lens can further include a lens communication line, a first lens power line, and a second lens power line which are respectively connected with associated lines of the camera body when the photographing lens is mounted to the camera body. The photographing lens communicates with the camera body via the lens communication line; the photographing lens receives the first power from the camera body via the first lens power line; and the photographing lens receives the second power from the camera body via the second lens power line.
It is desirable for the photographing lens to further include a control line for changing a state of the lens memory between an enabled state and a disabled state.
A camera system can be provided, including a camera body and a photographing lens which can be mounted to and dismounted from the camera body; wherein the photographing lens includes at least one of a lens memory, in which lens data on the photographing lens is stored, and an electronic device; wherein the camera body includes a body controller which can communicate with the lens memory, a first power which can be supplied to the photographing lens, and a second power which can be supplied to the photographing lens, a power capacity of the second power being greater than the first power. The lens memory and the electronic device operate with the first power and the second power, respectively, when the photographing lens is mounted to the camera body. The body controller supplies the first power to the photographing lens to drive the lens memory to read out the lens data from the lens memory when the photographing lens is mounted to the camera body. The body controller supplies the second power to the electronic device in the case where the body controller determines, from the lens data read out of the lens memory, that the photographing lens includes the electronic device.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-041896 (filed on Feb. 19, 2001) which is expressly incorporated herein by reference in its entirety.